In English, there are two articles that mean the same thing but are different by one letter: “a” and “an”. These articles are used to show that there is one thing of something. It is also used to show that you’re not talking about something specific.

Examples:

Can you give me an apple?

I would like to buy a dress.

We went to the grocery store to find a box of cereal.

Notice that in these examples, there is only one thing – only one apple, one dress, one box of cereal. Also, you do not know which apple or which dress. There are no details showing you which one. It could be any apple or any dress or any box of cereal.

I know that when you’re trying to learn the big things in English, these small words may seem insignificant. There are a few reasons to learn the difference between these two words and how to use them properly.

Be fluent. When you’re trying to become fluent, you need to identify the small things that you say or pronounce incorrectly so that you can narrow down your errors and mistakes. This will help you get to the point where you’re using less and less mistakes.

Pronunciation. Using these articles correctly helps with correct pronunciation, surprisingly. Using the correct word before others will help you pronounce the following words correctly.

Flow. In the same way that it helps with pronunciation, it also helps with the flow of your English. You will sound less choppy and more smooth when you’re speaking.

So what’s the difference? Which one do you use? Here are the rules:

Use “a” before a word that starts with a consonant. Use “an” before a word that starts with a vowel.

If you need a reminder of what a consonant or vowel is:

Consonant: all other letters that are not vowels

Vowel: the following letters – a, e, i, o , u

We use these articles in the following pattern: “a” or “an” + noun (or phrase indicating a noun) or object.

A/AN + NOUN

Examples of this pattern

an apple

a desk

a bottle of water

an elephant

an object

a piece of cake

an umbrella

In each example there is first the article (a/an) and then an object (or noun).

Examples of this pattern with sentences

Can you toss me an apple?

I just need a desk to work at.

She took a bottle of water to work.

An elephant is very large.

It can be an object of any kind.

It is a piece of cake.

I really need an umbrella right now.

Notice that the following examples use “a” because the following word starts with a consonant.

I just need a desk to work at.

She took a bottle of water to work.

It is a piece of cake.

Notice that the following examples use “an” because the following word starts with a vowel.

Can you toss me an apple?

An elephant is very large.

It can be an object of any kind.

I really need an umbrella right now.

At first when you’re trying to use the right article – a or an – it may take a second to think about which one is correct. Or you may correct yourself after you say the words. That is perfectly okay! It will take time to get used to it. And after time, it will come without you thinking about it. Just practice and practice. Try to correct yourself as you’re speaking or writing.

Exceptions

As always in English, there are a few exceptions to the rules.

Use “an” before a word that sounds like it starts with a vowel, such as “an hour”. Notice that in this word, you do not pronounce the “h” so it sounds like it starts with a vowel.

Use “a” before a word that sounds like it starts with a consonant, such as “a university.” Notice that in this word, the “u” letter makes a sound that sounds more like it starts with the letter “y”.